1. Field of the Invention
The present invention relates generally to scoring glass and other fracture sensitive sheet materials, and more particularly to a cutting machine having a plurality of cutting heads for creating a corresponding plurality of scorelines in such materials.
2. Description of the Prior Art
Cutting machines for scoring glass or other fracture sensitive sheet material (e.g., acrylic sheet) are known to the art. Cutting machines equipped with a plurality of cutting heads for simultaneously creating a plurality of parallel score lines in order to cut multiple strips of such materials are also known and are commercially available from the Fletcher-Terry Company of Farmington, Conn. Typically, the cutting heads used in conjunction with such multiple head cutting machines are of highly complex construction. One type of cutting head commonly used within such machines is pneumatically controlled, and hence the machine requires an air compressor for providing a source of pneumatic pressure. Another type of cutting head used within multiple head cutting machines is disclosed in U.S. Pat. No. 4,098,155, being designated therein as a self-compensating head. The self-compensating cutting head disclosed in the above mentioned patent includes a relatively large number of components and is therefore expensive.
For each of the above mentioned types of cutting heads, the operator must separately adjust each of the plurality of cutting heads if it is desired to change the pressure exerted by each of the cutting heads upon the material to be scored. The time which this procedure requires is, of course, directly proportional to the number of cutting heads attached to the cutting machine and becomes quite lengthy when several cutting heads are being used.
For cutting machines of the type described above, each of the cutting heads typically includes a cutting wheel which is drawn across the sheet material to create a score line therein. Scoring of glass sheets by a cutting wheel alone often results in flakes, slivers, or chips, along the score line, sometimes referred to in the trade as a "hot cut". Such flaking and chipping results in a ragged or rough edge after the glass is broken along the score line. To prevent a hot cut, a lubricant or cutting fluid, such as oil, is commonly applied either directly to the cutting wheel or to the glass sheet immediately adjacent the cutting wheel. The application of oil or other lubricant minimizes chipping along the score line and prolongs the life of the cutting wheel. One difficulty which has been experienced in the prior art is to adequately control the flow of such lubricating fluid. In U.S. Pat. No. 3,850,063, a valved type cutting wheel assembly is provided for regulating the flow of such lubricating fluid. However, the cutting wheel assembly disclosed in the above mentioned patent is necessarily complex and relatively expensive.
Another disadvantage of prior art cutting machines when used to score glass is that they tend to create chips in the edge of the glass. As the cutting wheel within each cutting head reaches thhe edge of the glass, the cutting wheel tends to ride down over the edge which often results in the creation of chips. In order to minimize such chipping at the edges of the glass being scored, the operator of the glass machine typically moves the cutting heads much more slowly as the cutting heads approach the edge of the glass. Although this procedure tends to minimize such chipping, it also lengthens the time required to make each cut, resulting in decreased production efficiency.
Accordingly, it is an object of the present invention to provide a cutting machine having a plurality of cutting heads for scoring a fracture sensitive sheet material while eliminating the requirement for an air compressor and associated pneumatic controls in order to operate the cutting machine.
Another object of the present invention is to provide a cutting machine having a plurality of cutting heads for scoring a fracture sensitive sheet material wherein the plurality of cutting heads are of simple construction and are relatively inexpensive.
Still another object of the present invention is to provide a cutting machine having a plurality of cutting heads for scoring a fracture sensitive sheet material wherein the pressure exerted by each of the cutting heads against the sheet material can be quickly and easily adjusted regardless of the number of cutting heads being used.
A further object of the present invention is to provide a cutting machine having a plurality of cutting heads for scoring a fracture sensitive sheet material wherein the machine can be manually operated with a single handle for simultaneously contacting the plurality of cutting heads against the sheet material to be scored and moving the cutting heads thereacross.
A still further object of the present invention is to provide a cutting machine having a plurality of cutting heads for scoring a fracture sensitive sheet material wherein each of the cutting wheels within the plurality of cutting heads may be simultaneously lubricated in a convenient and non-complex manner.
It is a still further object of the present invention to provide a method of efficiently cutting a fracture sensitive sheet material while minimizing chipping at the edges thereof.
These and other objects of the present invention will become apparent to those skilled in the art as the description thereof proceeds.